Prohobited sign at MacBook startup

So I keep getting a prohibited sign when I boot up my MacBook pro running Snow

I read it was because a file was corrupted and I need to reinstall Snow Leopard

Well, I inster my Snow Leopard start disk, and hold down C when I hear the chime
I hold it down, I hear the disk in the drive boot up, spin fast, Apple has the progress wheel under it but nothing happens.

Same story with the Leopard install disk

Yes, my drive does work and is fully functional

Now, with my Leopard disk, when I hold down C, (i hold it down for at least 4 to 5 minutes)

The screen goes dark gray and a screen comes up saying "You need to restart your Mac, please hold down power button"

Hmm....I am having the exact same problem with my 13" MBP that started today. I was about to look for a place to post and saw your question.

I am right now booted from an external back up I had made with super duper, but my OS X install CD cannot even see my internal disk. However, it has been able to start up a couple of times, and when I can start from the disk, the SMART status shows up as verified.

I took the drive out and reseated it with the same results. It seems like if the drive is bad the SMART status should say it's failing, so I don't get it. I *need* this computer to be working, and I ordered a box from AppleCare to send it in, but I am trying to think of a solution myself. I am contemplating buying a new internal hard drive for it, but I don't know the first thing about buying internal drives. I am sort of frantic right now, and I will read around about buying a drive, but if anyone has any advice, I'll take it.

Hmm....I am having the exact same problem with my 13" MBP that started today. I was about to look for a place to post and saw your question.

I am right now booted from an external back up I had made with super duper, but my OS X install CD cannot even see my internal disk. However, it has been able to start up a couple of times, and when I can start from the disk, the SMART status shows up as verified.

I took the drive out and reseated it with the same results. It seems like if the drive is bad the SMART status should say it's failing, so I don't get it. I *need* this computer to be working, and I ordered a box from AppleCare to send it in, but I am trying to think of a solution myself. I am contemplating buying a new internal hard drive for it, but I don't know the first thing about buying internal drives. I am sort of frantic right now, and I will read around about buying a drive, but if anyone has any advice, I'll take it.

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From what I have researched, unless your hard drive is clicking or has problems, the reason why the prohobited sign comes up because a file in your drive is corrupted...The OSX Install should fix it...I just can't get it to boot...

From what I have researched, unless your hard drive is clicking or has problems, the reason why the prohobited sign comes up because a file in your drive is corrupted...The OSX Install should fix it...I just can't get it to boot...

I'll let you know if I find anything else...

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Hmm...I went to reinstall OS X, and every time I do it can't even find the drive to install onto! It seems like if it can't find the drive it must be more than a corrupted file, right? Plus it's running fine from the same OS X install I have backed up to an external drive...thanks heavens for super duper....

With regard to booting up to the CD, try holding down the option key when you boot up to see if you can select your OS X install CD that way.

By "prohibited sign"... do you mean a circle with a diagonal line through it? This happened to me today as well on my 15" MBP running 10.5.8

I went to work, booted my machine and after the apple logo displays for a bit, then I get the circle with diagonal line, and it hangs.

I rushed home, pulled the SSD, and replaced it with the original HDD and was able to boot right away.

Did anyone else have any problems today?

/Jim

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Yes, the "Do not enter" sign...I've been calling it the prohibitory sign as I saw an apple support document that called it that.

Since you seem to know about hard drives a bit, as you mentioned replacing your drive, maybe if I explain my situation a bit more you could try to help me determine whether it's the cable or the drive.

I was using my computer when one by one applications started hanging. It resolved itself, and then they all started hanging again. I had to power it down, and when I restarted i got the prohibitory sign. However, on the odd occasion it would start up but applications would eventually hang. However, it seemed items already in memory would work. For example, if I had a safari page open, I could scroll up and down, but as soon as I closed the window, I couldn't open a new window or even use the menu bar. It made me think that the signal from the hard disk was coming intermittently rather than it being a bad drive. And then at times there seemed to be no signal from the drive as it would just start up to a gray screen or the hard disk wouldn't show up when booted to the OS X install CD. But the times it was starting up, I wonder if the signal was getting through and when it would hang was when it wasn't coming through. And as well when it wouldn't boot to the gray screen or prohibitory screen it was the signal not coming through.

Do you think I should buy a new drive and try it, or do you think I should (arg) send it in and it might be the cable?

Yes, the "Do not enter" sign...I've been calling it the prohibitory sign as I saw an apple support document that called it that.

Since you seem to know about hard drives a bit, as you mentioned replacing your drive, maybe if I explain my situation a bit more you could try to help me determine whether it's the cable or the drive.

I was using my computer when one by one applications started hanging. It resolved itself, and then they all started hanging again. I had to power it down, and when I restarted i got the prohibitory sign. However, on the odd occasion it would start up but applications would eventually hang. However, it seemed items already in memory would work. For example, if I had a safari page open, I could scroll up and down, but as soon as I closed the window, I couldn't open a new window or even use the menu bar. It made me think that the signal from the hard disk was coming intermittently rather than it being a bad drive. And then at times there seemed to be no signal from the drive as it would just start up to a gray screen or the hard disk wouldn't show up when booted to the OS X install CD. But the times it was starting up, I wonder if the signal was getting through and when it would hang was when it wasn't coming through. And as well when it wouldn't boot to the gray screen or prohibitory screen it was the signal not coming through.

Do you think I should buy a new drive and try it, or do you think I should (arg) send it in and it might be the cable?

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I cannot tell if your problem is a bad drive, or a bad connection. I do know that in my case, when I changed the drive (from my SSD back to my original HDD), the problem went away. I thought that maybe my SSD had failed. However, after putting my MBP back together, I attached the SSD through a SATA - USB connection... and I was able to boot from my SSD just fine. That made me wonder if it was just a poor connection to my SSD that caused the problem.

I have not tried to put the SSD back into the computer yet. I also have an extra SSD that I could burn and install if necessary.

OTOH... I will be getting a new MBP from work soon after the next versions are released... so I just may wait and keep the machine as is for a while. I really cannot afford the down time if my machine goes unstable.

I cannot tell if your problem is a bad drive, or a bad connection. I do know that in my case, when I changed the drive (from my SSD back to my original HDD), the problem went away. I thought that maybe my SSD had failed. However, after putting my MBP back together, I attached the SSD through a SATA - USB connection... and I was able to boot from my SSD just fine. That made me wonder if it was just a poor connection to my SSD that caused the problem.

I have not tried to put the SSD back into the computer yet. I also have an extra SSD that I could burn and install if necessary.

OTOH... I will be getting a new MBP from work soon after the next versions are released... so I just may wait and keep the machine as is for a while. I really cannot afford the down time if my machine goes unstable.

/Jim

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Very odd....so both of your disks are good, yet your internal hard drive cable suddenly stopped working with your SSD but still works with your HDD. It's similar in the way mine suddenly stopped working but the drive doesn't seem to be bad. If I got hold of one of those SATA to USB connectors you're talking about, I didn't know such things existed, I could test my theory that it's my cable not working...you get quite an education when disasters strike. I didn't even know what SATA was before this evening.

I called the Apple Store and they told me a hard drive swap could take 3-5 days meaning they are either very busy or do hard drive swaps in slow motion. So even though I'm under warranty I bought a new drive. I wanted to buy the Hitachi Travelstar 500 GB 7200 RPM, but I also wanted the drive here tomorrow so my only option was to get the 320 GB 7200 RPM Travelstar via Amazon saturday delivery.

I am a bit nervous--as I am not at all a hardware guy. I will follow the ifixit.com instructions I found, but I am even more worried it's not actually the hard drive but the cable. There's also the possibility it's a corrupted file, but I can't see anywhere online where it says a corrupted file would make the drive invisible to the computer.

So, I got the drive today, installed it, tried booting up from the OS X install CD, and it wouldn't boot to that (it had been before I installed the new drive). Tried booting to my external drive and it wouldn't boot. Zapped the PRAM, still wouldn't boot. So, I tried again booting to the install CD and I let it run for a half hour or so and it finally came up to the Choose your Language screen. It took about 10 minutes for it to register me hitting English and continue. After that, it worked at normal speed. I went to Disk Utility, and it couldn't see the new drive. I went to install OS X, couldn't see the new drive.

So, I booted again to my external drive. It took about a half hour to boot, and once it booted it took about 10 minutes for it to register my first click--again after that, it's now working at regular speed. VERY strange.

It's not showing the drive from here either. Interestingly, I opened the system profiler and went to the Serial-ATA section and it says, "There was an error while scanning for Serial-ATA devices."

So more proof it's the cable I guess. But if it's just the hard drive cable, what is causing the boot ups from the CD and external drive to be so slow?

So my options at this point are to mail it to Apple, or order a new SATA cable and try installing it myself. I need the computer and don't want the downtime. On the other hand--what if it's not the cable that's the problem? And if I buy the cable, do I buy a used one from ifixit (they apparently sell ones from old computers), or do I try to find a generic SATA cable (perhaps of better quality than Apple's), and would that even work?

I'm exhausted and stressed at this point, but I wanted to write this out for cathartic reasons I suppose. I'm going to take a nap and sleep on this before researching SATA cable replacements . . .

If anyone wants to save me any legwork and has advice, I'm happy to hear it!

It looks like I have the same problem... Bought the Intel X25-M G2 80GB and an Optibay. First tried to put the drive directly in the bay but the mac would not see it after a very slow boot. Decided OK, must probably format it first and did that through an external enclosure (HFS+, Journaled). SSD was working fine there. Tried to put it again in the optibay, very slow boot and the SSD is not seen by the system. Through System Profiler, I get the "There was an error while scanning for Serial-ATA devices." message in the SATA tab... I'm about to try to plug back the DVD drive and see if it works...

It looks like I already damaged my speaker cable while doing all this, and I might have messed up the SATA connector or the cable too... Great, I really feel like a retard

Put the SSD in the regular HDD slot and it works fine... Put my regular HDD in the Optibay and it's still not recognized, although I don't have the SATA scanning error. The drive just doesn't show up in the System Profiler... So it's narrowing it down to some issue with my SATA port on the optical drive no? Is it fundamentally different to have an optical drive or an HDD/SSD there? Some help would be appreciated...

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